Why is there an x86 emu if a processor is x86-64?

I don't quite understand the approach Microsoft has taken with x64. I have an
AMD Athlon 64 3500+, and it supports both 64bit instructions and the 32bit.
So why is x64 emulating the 32bit instructions while my CPU can interpret
them natively? Wouldn't that give me better program/driver support? If this
is something that would require some long explanation (like if its something
that involves the kernel's inner workings) then don't worry about it much and
just say "its the kernel" or somethin, I'll get ya.

Advertisements

Seriously, it _does_ take advantage of the native support. But there still
needs to have a very thin layer that translates between the 64 bit OS and
the 32-bit application. This layer really doesn't impose any overhead, and
many 32-bit programs actually appear faster in 64bit, though it really
depends a lot on the program. The 64bit I/O subsystem is definitely more
efficient, however, so programs that use a lot of I/O can sometimes be
faster in 64 bit windows even though they are 32bit programs and they run in
the WOW64 subsystem. There's a good graphic of this in the whitepaper I
wrote for Microsoft: http://download.microsoft.com/downl..._XP_Professional_x64_Edition_Right_for_Me.doc

Elliot Hudgins wrote:
> I don't quite understand the approach Microsoft has taken with x64. I
> have an AMD Athlon 64 3500+, and it supports both 64bit instructions and
> the 32bit. So why is x64 emulating the 32bit instructions while my CPU
> can interpret them natively? Wouldn't that give me better program/driver
> support? If this is something that would require some long explanation
> (like if its something that involves the kernel's inner workings) then
> don't worry about it much and just say "its the kernel" or somethin, I'll
> get ya.
>
> Thanks a lot!
> Elliot

Advertisements

Wow! Your paper is really, really thought out and explained pretty much
everything I needed to know! Thanks a lot for the info. I guess that I just
wished for 32 bit drivers to work in 64, I miss my tuner

Let's all hope that driver support gets better once Vista comes around
Oh, and do you know if it will have some type of megalo-awesome emulation
layer that WILL run 32-bit drivers? If you say it will, I'll love you.
Forever. Not in the man to man way, but I'll give you a hug in public and not
think twice.

Elliot

"Charlie Russel - MVP" wrote:
> The kernel.
>
> Seriously, it _does_ take advantage of the native support. But there still
> needs to have a very thin layer that translates between the 64 bit OS and
> the 32-bit application. This layer really doesn't impose any overhead, and
> many 32-bit programs actually appear faster in 64bit, though it really
> depends a lot on the program. The 64bit I/O subsystem is definitely more
> efficient, however, so programs that use a lot of I/O can sometimes be
> faster in 64 bit windows even though they are 32bit programs and they run in
> the WOW64 subsystem. There's a good graphic of this in the whitepaper I
> wrote for Microsoft:
> http://download.microsoft.com/downl..._XP_Professional_x64_Edition_Right_for_Me.doc
>
> You might find it of interest.
>
> --
> Charlie.
> http://msmvps.com/xperts64
>
>
> Elliot Hudgins wrote:
> > I don't quite understand the approach Microsoft has taken with x64. I
> > have an AMD Athlon 64 3500+, and it supports both 64bit instructions and
> > the 32bit. So why is x64 emulating the 32bit instructions while my CPU
> > can interpret them natively? Wouldn't that give me better program/driver
> > support? If this is something that would require some long explanation
> > (like if its something that involves the kernel's inner workings) then
> > don't worry about it much and just say "its the kernel" or somethin, I'll
> > get ya.
> >
> > Thanks a lot!
> > Elliot
>
>
>

No, no 32bit system level drivers. In fact, ALL drivers in 64bit Vista must
be signed. Personally, I'm glad MS is taking this step, even though I know
it may, in the short term, make things slightly worse. In the long term,
we'll all benefit. And with the logo requirements for Vista, I think we'll
see the driver situation get a lot better.

Elliot Hudgins wrote:
> Wow! Your paper is really, really thought out and explained pretty much
> everything I needed to know! Thanks a lot for the info. I guess that I
> just wished for 32 bit drivers to work in 64, I miss my tuner
>
> Let's all hope that driver support gets better once Vista comes around
> Oh, and do you know if it will have some type of megalo-awesome emulation
> layer that WILL run 32-bit drivers? If you say it will, I'll love you.
> Forever. Not in the man to man way, but I'll give you a hug in public and
> not think twice.
>
> Elliot
>
> "Charlie Russel - MVP" wrote:
>
>> The kernel.
>>
>> Seriously, it _does_ take advantage of the native support. But there
>> still needs to have a very thin layer that translates between the 64 bit
>> OS and the 32-bit application. This layer really doesn't impose any
>> overhead, and many 32-bit programs actually appear faster in 64bit,
>> though it really depends a lot on the program. The 64bit I/O subsystem
>> is definitely more efficient, however, so programs that use a lot of I/O
>> can sometimes be faster in 64 bit windows even though they are 32bit
>> programs and they run in the WOW64 subsystem. There's a good graphic of
>> this in the whitepaper I wrote for Microsoft:
>> http://download.microsoft.com/downl..._XP_Professional_x64_Edition_Right_for_Me.doc
>>
>> You might find it of interest.
>>
>> --
>> Charlie.
>> http://msmvps.com/xperts64
>>
>>
>> Elliot Hudgins wrote:
>>> I don't quite understand the approach Microsoft has taken with x64. I
>>> have an AMD Athlon 64 3500+, and it supports both 64bit instructions and
>>> the 32bit. So why is x64 emulating the 32bit instructions while my CPU
>>> can interpret them natively? Wouldn't that give me better program/driver
>>> support? If this is something that would require some long explanation
>>> (like if its something that involves the kernel's inner workings) then
>>> don't worry about it much and just say "its the kernel" or somethin,
>>> I'll get ya.
>>>
>>> Thanks a lot!
>>> Elliot

"Elliot Hudgins" <> wrote in message
news:...
> Wow! Your paper is really, really thought out and explained pretty much
> everything I needed to know! Thanks a lot for the info. I guess that I
> just
> wished for 32 bit drivers to work in 64, I miss my tuner
>
> Let's all hope that driver support gets better once Vista comes around
> Oh, and do you know if it will have some type of megalo-awesome emulation
> layer that WILL run 32-bit drivers? If you say it will, I'll love you.
> Forever. Not in the man to man way, but I'll give you a hug in public and
> not
> think twice.
>
> Elliot
>
> "Charlie Russel - MVP" wrote:
>
>> The kernel.
>>
>> Seriously, it _does_ take advantage of the native support. But there
>> still
>> needs to have a very thin layer that translates between the 64 bit OS and
>> the 32-bit application. This layer really doesn't impose any overhead,
>> and
>> many 32-bit programs actually appear faster in 64bit, though it really
>> depends a lot on the program. The 64bit I/O subsystem is definitely more
>> efficient, however, so programs that use a lot of I/O can sometimes be
>> faster in 64 bit windows even though they are 32bit programs and they run
>> in
>> the WOW64 subsystem. There's a good graphic of this in the whitepaper I
>> wrote for Microsoft:
>> http://download.microsoft.com/downl..._XP_Professional_x64_Edition_Right_for_Me.doc
>>
>> You might find it of interest.
>>
>> --
>> Charlie.
>> http://msmvps.com/xperts64
>>
>>
>> Elliot Hudgins wrote:
>> > I don't quite understand the approach Microsoft has taken with x64. I
>> > have an AMD Athlon 64 3500+, and it supports both 64bit instructions
>> > and
>> > the 32bit. So why is x64 emulating the 32bit instructions while my CPU
>> > can interpret them natively? Wouldn't that give me better
>> > program/driver
>> > support? If this is something that would require some long explanation
>> > (like if its something that involves the kernel's inner workings) then
>> > don't worry about it much and just say "its the kernel" or somethin,
>> > I'll
>> > get ya.
>> >
>> > Thanks a lot!
>> > Elliot
>>
>>
>>

Share This Page

Welcome to Velocity Reviews!

Welcome to the Velocity Reviews, the place to come for the latest tech news and reviews.

Please join our friendly community by clicking the button below - it only takes a few seconds and is totally free. You'll be able to chat with other enthusiasts and get tech help from other members.
Sign up now!